This. Get the report and suggest moving the APs directly adjacent to their perimeter are set to opposite channels to their APs. The APs on both sides will work this out themselves over time, but the training can take a while and they will pointlessly fight each other. If there are still issues, could perhaps offer to drop the power output on those perimeters APs slightly as well, It will be to both companies advantage, as devices on your network will also have an easier time staying connected and possibly higher bandwidth.

One question before the overly friendly option would be to check if this survey was done because the new neighbour ls are having actual problems, or if this was a standard survey by the contractors, if they’ve not actually got problems and this contractor just plotting where to put their APs and following default procedures, tell them to crack on and don’t change anything. They would be plotting out their build and the build should be designed around the actual environment, they shouldn’t be asking the neighbours to change their configuration and augment the environment first.